It's not stealing, it's forcing you to share your know-how (sometimes patented, but perhaps not in China) in exchange to access to market. That includes training of workers (sort of like graduates joining Google, leaving getting trained, after a couple of years they leave and establish a startup).

The other side of this is takeovers in the West - sometimes they get blocked by government, like quite recently in Germany.

The West wanted cheap workforce, it came with a hefty price that will be paid years later after WTO admission, didn't you know?